Randy Libner
(K=4084) - Comment Date 9/27/2005
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That's normal.... that's what film is.... grains. Faster film shows more graininess than slow film.
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Jeroen Wenting
(K=25317) - Comment Date 9/28/2005
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The light sensitive chemicals on a film base are made up of small crystals (usually) of chemicals which are sensitive to a particular band of frequencies in the electromagnetic spectrum (read: wavelengths of light).
These are spread on the film in layers, with usually each layer being a different chemical with different characteristics.
By combining different chemicals and layers manufacturers can create different film characteristics.
The size of the crystals is (in part) responsible for the light sensitivity. A larger crystal is more likely to catch a photon and thus react.
In practice the crystals are clumped together with each clump reacting like a single crystal.
The larger the clump, the more sensitive the film.
These clumps of photosensitive material are called grains, the size and shape of the grain described as graininess.
Sometimes small grains can appear larger than they really are under harsh light (like a scanner) because of their shape, making the film hard to scan (Fuji NPS is an example of this).
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Helen Bach
(K=2331) - Comment Date 9/28/2005
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There could be another explanation, especially if you are looking at bright midtones in low speed colour film: the dye clouds (the ?grains?) may be too small for your projector lens to resolve - projector lenses don't usually have really high resolution. The 'grains' are always there in the film, but they can be very small. If your lens could resolve them, they would be visible upon enlargement. Your loupe may actually have a higher resolving power than your projector lens.
Apart from being careful with the focussing, you could try 'stopping down' your projector lens by making a simple 'stop' from a piece of black paper - a circular hole in the paper, about half the diameter of your lens.
Best,
Helen
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Helen Bach
(K=2331) - Comment Date 9/28/2005
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Oh, and I've just noticed that you are projecting onto a wall. For critical work you can project onto a piece of plain white paper - it can be smaller than the full image, of course.
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Helen Bach
(K=2331) - Comment Date 9/28/2005
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... and, still thinking ... have you tried putting the loupe on your light panel without a slide?
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Elangovan S
(K=10675) - Comment Date 9/29/2005
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Yes, I just put kept the loupe on the light panel and I didnt notice any grainy structure.
Elangs.
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Elangovan S
(K=10675) - Comment Date 9/29/2005
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Thanks all for the great insight about the films. Will explore more on this.
Elangs.
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carlos sanchez
(K=3631) - Comment Date 10/5/2005
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yo creo que no es el grano,que sera polvo que se ha depositado en la diapositiva,o en la superficie donde se proyecta.
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